The ether of the invention has been traditionally prepared by the use of a strong mineral acid, e.g. sulfuric acid. Such strong acids under the process conditions are very corrosive and cause significant problems when applied on a commercial scale. As a result, there has been a continuous search for an improved process of high efficiency that avoids these corrosion problems.
Acidic ion exchange resins, which also have been used as catalysts for the preparation of the ethers of the invention, cannot be used at temperatures higher than 70.degree.-75.degree. C. due to their poor thermal stability. This limitation results in long reaction times and low throughput per unit volume of a reaction vessel.
Another problem associated with the known processes is the formation of undesirably large quantities of dimethyl ether. The present invention also deals with this problem and substantially reduces the amount of this undesirable by-product.